Malignant peritoneal mesothelioma: a rare but fatal tumor with non-specific symptoms

SESSION TITLE: Critical Care Case Report Posters 38 SESSION TYPE: Case Report Posters PRESENTED ON: 10/10/2023 09:40 am - 10:25 am INTRODUCTION: Malignant peritoneal mesothelioma (MPM) is a rare tumor accounting for 7-30% cases of malignant mesothelioma. We report the case of a patient who presented with abdominal pain due to perforation of the large bowel and found to have MPM. CASE PRESENTATION: An 85-year-old male with multiple comorbidities presented with sudden onset abdominal pain without any associated symptoms. He was a former smoker without any significant current or past exposures. Patient was hemodynamically stable with decreased bowel sounds in the right upper quadrant, abdominal distention and mild generalized tenderness without guarding, rebound, or rigidity. Laboratory data showed leukocytosis and lactic acidosis. Imaging studies showed free intraperitoneal air with wall thickening in distal stomach and space-occupying lesions in the liver (Figure 1). Patient was started on antibiotic therapy with gram-negative and anaerobic coverage. Exploratory laparotomy was performed which showed perforation of the transverse colon with fecal peritonitis without any masses. Whitish deposits were seen in the resected omentum. Patient underwent a right hemicolectomy with ileostomy. Pathologic examination of the right colon and omentum illustrated malignant neoplasm composed of spindle cells and epithelioid cells forming acinar structures indicating mesothelioma with peritoneal involvement (Figures 2). Immunohistochemistry (IHC) staining was positive for keratin AE1/AE3, OSCAR keratin, calretinin, and Wilms tumor-1 (WT1) (Figures 3). Patient was deemed to be a poor candidate for further therapy and was discharged home with hospice care. DISCUSSION: Most cases of MPM present with nonspecific symptoms like abdominal distension. Ascites can be seen occasionally. Complications like bowel obstruction and perforation can occur and when present, might be life threatening. Computed tomography (CT) scan of the abdomen is usually the initial diagnostic testing and may show soft tissue mass with enhancement. Use of Other imaging modalities like MRI is still being evaluated [1]. Definitive diagnosis of MPM is made by pathologic evaluation with three distinct histologic patterns epithelioid, sarcomatoid, and biphasic/mixed which is a combination of the first two patterns [2]. Positive IHC staining for epithelial membrane antigen (EMA), cytokeratin 5/6, WT-1 also distinguishes MPM from other histologically similar appearing malignancies [2,3]. Once staged, the mainstay of treatment is cytoreductive surgery (CRS) with heated intraperitoneal chemotherapy (HIPEC) in appropriate candidates. Untreated patients have a median survival of five to twelve months while CRS-HIPEC can increase survival up to 38- 92 months. Chemotherapy is another option for patients who are not eligible for CRS-HIPEC, and cisplatin or carboplatin are first line agents. Current research is identifying targetable molecular pathways in MPM that can be used for further treatment options such as epidermal growth factors receptor (EGFR) inhibitors [3]. CONCLUSIONS: MPM is a very rare disease with nonspecific symptoms and presentation, making diagnosis extremely challenging. Extensive peritoneal spread makes the disease ultimately fatal. Thereby, timely diagnosis is crucial, especially with advances in surgical and chemotherapeutic options including targeted molecular therapy. REFERENCE #1: Deraco, M., Bartlett, D., Kusamura, S., & Baratti, D. (2008). Consensus statement on peritoneal mesothelioma. Journal of surgical oncology, 98(4), 268–272. https://doi.org/10.1002/jso.21055 REFERENCE #2: Robinson, B. W., & Lake, R. A. (2005). Advances in malignant mesothelioma. The New England journal of medicine, 353(15), 1591–1603. https://doi.org/10.1056/NEJMra050152 REFERENCE #3: Kim, J., Bhagwandin, S., & Labow, D. M. (2017). Malignant peritoneal mesothelioma: a review. Annals of translational medicine, 5(11), 236. https://doi.org/10.21037/atm.2017.03.96 DISCLOSURES: No relevant relationships by Mohammed Ali No relevant relationships by Asad Chohan No relevant relationships by Saiara Choudhury No relevant relationships by Austin Makadia No relevant relationships by Vashistha Patel No relevant relationships by Vishesh Persaud No relevant relationships by Abhay Vakil